1. DHCPv6 Dynamic Reconfigure draft-wing-dhc-dns-reconfigure-02 P.Patil, M.Boucadair, T.Reddy, D.Wing IETF-88 Presenter: Shwetha Bhandari DHCPv6 Dynamic Reconfigure1

2. Updates from 01-02 Option from Relay in Relay-Forw to indicate if client is single/dual stacked Generic message from Relay to indicate host mode transitions to the server – IPv4 to Dual-Stack – IPv6 to Dual-Stack – Dual-Stack to IPv4 – Dual-Stack to IPv6 DHCPv6 Server acts accordingly on the generic message DHCPv6 Dynamic Reconfigure2

3. Problem Hosts connected to a network may be IPv4-only, IPv6-only or dual-stack Returning generic configuration to all such hosts may not be optimal and in some cases may raise complications Typical examples with problems are – Provide a DNS server to an IPv6-only host, while DNS64 is required – Provision a DNS64 server to a dual-stack host DHCPv6 Dynamic Reconfigure3

4. Focus on a Use Case Avoid unnecessary NAT64 by influencing the host's DNS server selection to use:  DNS64 when IPv6-only  Normal DNS when dual-stack Static configuration is sub-optimal in heterogeneous environments and during host mode transitions DHCPv6 Dynamic Reconfigure4

5. 5 Relay-Forward IPv4 Stack Initializes Transition to Dual-Stack DHCP Request Relay Forward Relay Reply DHCP Response DHCP Request Relay Forward w/ Dual-Stack indication Relay Reply DHCP Response NAS (DHCP Relay)DHCP Server DHCP Client

6. DHCPv6 Dynamic Reconfigure6 Reconfigure-Request Dual Stack host Transitions to IPv4/6 only Reconfigure Request w/ Dual-Stack transition indication Relay Reply (Reconfigure) Reconfigure NAS (DHCP Relay)DHCP Server DHCP Client Relay detects transition Reconfigure-Reply

7. Next Steps This is a missing piece of work Request adoption by the WG DHCPv6 Dynamic Reconfigure7